[moderation] [kernel?] KASAN: stack-out-of-bounds Read in unwind_next_frame (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f76698bd9a8c Add linux-next specific files for 20240621
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12f0a161980000
kernel config: https://syzkaller.appspot.com/x/.config?x=ca79e3c3b9118bd0
dashboard link: https://syzkaller.appspot.com/bug?extid=bb795045188b80a0f610
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [b...@alien8.de dave....@linux.intel.com h...@zytor.com jpoi...@kernel.org linux-...@vger.kernel.org mi...@redhat.com pet...@infradead.org tg...@linutronix.de x...@kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f204c5d02251/disk-f76698bd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/50289c7e8999/vmlinux-f76698bd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c360e133a94f/bzImage-f76698bd.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bb7950...@syzkaller.appspotmail.com

RBP: dffffc0000000000 R08: ffffffff8a2d136b R09: 1ffffffff25fc8e8
R10: dffffc0000000000 R11: fffffbfff25fc8e9 R12: ffffc900041576a0
R13: ffff8880291b0700 R14: ffff8880291b0700 R15: 1ffff110052360e0
==================================================================
BUG: KASAN: stack-out-of-bounds in user_mode arch/x86/include/asm/ptrace.h:214 [inline]
BUG: KASAN: stack-out-of-bounds in unwind_next_frame+0x2177/0x2a00 arch/x86/kernel/unwind_orc.c:482
Read of size 2 at addr ffffc900041575d0 by task syz-executor.2/7607

CPU: 1 UID: 0 PID: 7607 Comm: syz-executor.2 Not tainted 6.10.0-rc4-next-20240621-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
user_mode arch/x86/include/asm/ptrace.h:214 [inline]
unwind_next_frame+0x2177/0x2a00 arch/x86/kernel/unwind_orc.c:482
show_trace_log_lvl+0x381/0x520 arch/x86/kernel/dumpstack.c:296
sched_show_task+0x578/0x740 kernel/sched/core.c:7503
report_rtnl_holders+0x1ba/0x2d0 net/core/rtnetlink.c:104
call_timer_fn+0x18e/0x650 kernel/time/timer.c:1792
expire_timers kernel/time/timer.c:1843 [inline]
__run_timers kernel/time/timer.c:2417 [inline]
__run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2428
run_timer_base kernel/time/timer.c:2437 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2447
handle_softirqs+0x2c4/0x970 kernel/softirq.c:554
__do_softirq kernel/softirq.c:588 [inline]
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637
irq_exit_rcu+0x9/0x30 kernel/softirq.c:649
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:finish_task_switch+0x1ea/0x870 kernel/sched/core.c:5123
Code: c9 50 e8 69 b8 0b 00 48 83 c4 08 4c 89 f7 e8 dd 38 00 00 e9 de 04 00 00 4c 89 f7 e8 30 a6 34 0a e8 ab 84 37 00 fb 48 8b 5d c0 <48> 8d bb f8 15 00 00 48 89 f8 48 c1 e8 03 49 be 00 00 00 00 00 fc
RSP: 0018:ffffc90003c57288 EFLAGS: 00000282
RAX: 9195a65d1261f900 RBX: ffff888024c8da00 RCX: ffffffff816fd09a
RDX: dffffc0000000000 RSI: ffffffff8bcac8a0 RDI: ffffffff8c206c80
RBP: ffffc90003c572d0 R08: ffffffff92fe47ef R09: 1ffffffff25fc8fd
R10: dffffc0000000000 R11: fffffbfff25fc8fe R12: 1ffff110172a7ec7
R13: dffffc0000000000 R14: ffff8880b943e8c0 R15: ffff8880b953f638
context_switch kernel/sched/core.c:5252 [inline]
__schedule+0x17f0/0x4a20 kernel/sched/core.c:6594
preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6773
preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6797
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
_raw_spin_unlock_irqrestore+0x130/0x140 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
__wake_up_common_lock+0x18c/0x1e0 kernel/sched/wait.c:108
__unix_dgram_recvmsg+0x5f4/0x12f0 net/unix/af_unix.c:2415
sock_recvmsg_nosec+0x18e/0x1d0 net/socket.c:1046
____sys_recvmsg+0x3c0/0x470 net/socket.c:2814
___sys_recvmsg net/socket.c:2858 [inline]
do_recvmmsg+0x474/0xae0 net/socket.c:2952
__sys_recvmmsg net/socket.c:3031 [inline]
__do_sys_recvmmsg net/socket.c:3054 [inline]
__se_sys_recvmmsg net/socket.c:3047 [inline]
__x64_sys_recvmmsg+0x199/0x250 net/socket.c:3047
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc27d67d0a9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc27e3920c8 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007fc27d7b4050 RCX: 00007fc27d67d0a9
RDX: 0000000000010106 RSI: 00000000200000c0 RDI: 0000000000000003
RBP: 00007fc27d6ec074 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007fc27d7b4050 R15: 00007fff5b81d208
</TASK>

The buggy address belongs to the virtual mapping at
[ffffc90004150000, ffffc90004159000) created by:
copy_process+0x5d1/0x3d90 kernel/fork.c:2206

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2226b
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x2dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_NOWARN|__GFP_ZERO), pid 2, tgid 2 (kthreadd), ts 7469715658, free_ts 0
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1500
prep_new_page mm/page_alloc.c:1508 [inline]
get_page_from_freelist+0x2ccb/0x2d80 mm/page_alloc.c:3487
__alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4745
alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2263
vm_area_alloc_pages mm/vmalloc.c:3576 [inline]
__vmalloc_area_node mm/vmalloc.c:3652 [inline]
__vmalloc_node_range_noprof+0x971/0x1460 mm/vmalloc.c:3833
alloc_thread_stack_node kernel/fork.c:313 [inline]
dup_task_struct+0x444/0x8c0 kernel/fork.c:1114
copy_process+0x5d1/0x3d90 kernel/fork.c:2206
kernel_clone+0x226/0x8f0 kernel/fork.c:2788
kernel_thread+0x1bc/0x240 kernel/fork.c:2850
create_kthread kernel/kthread.c:412 [inline]
kthreadd+0x60d/0x810 kernel/kthread.c:765
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:144
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
page_owner free stack trace missing

Memory state around the buggy address:
ffffc90004157480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffc90004157500: 00 00 00 00 f1 f1 f1 f1 00 00 00 f2 f2 f2 f2 f2
>ffffc90004157580: 04 f2 00 f2 f2 f2 00 00 f3 f3 f3 f3 00 00 00 00
^
ffffc90004157600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffc90004157680: 00 00 00 00 f1 f1 f1 f1 00 00 00 00 00 f2 f2 f2
==================================================================
----------------
Code disassembly (best guess):
0: c9 leave
1: 50 push %rax
2: e8 69 b8 0b 00 call 0xbb870
7: 48 83 c4 08 add $0x8,%rsp
b: 4c 89 f7 mov %r14,%rdi
e: e8 dd 38 00 00 call 0x38f0
13: e9 de 04 00 00 jmp 0x4f6
18: 4c 89 f7 mov %r14,%rdi
1b: e8 30 a6 34 0a call 0xa34a650
20: e8 ab 84 37 00 call 0x3784d0
25: fb sti
26: 48 8b 5d c0 mov -0x40(%rbp),%rbx
* 2a: 48 8d bb f8 15 00 00 lea 0x15f8(%rbx),%rdi <-- trapping instruction
31: 48 89 f8 mov %rdi,%rax
34: 48 c1 e8 03 shr $0x3,%rax
38: 49 rex.WB
39: be 00 00 00 00 mov $0x0,%esi
3e: 00 fc add %bh,%ah


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[Aleksandr Nogikh]

#syz upstream

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